US7167084B2 - Temporary key invalidation for electronic key and locking system - Google Patents

Abstract

Methods and apparatus are provided for rendering electronic keys left behind in a vehicle temporarily inactive. The apparatus comprises a vehicle security control module in wireless communication with the electronic keys, and having operatively coupled together a receiver, a processor, non-volatile memory and a short-range transmitter. When the module receives a valid lock command from any source it sends a short-range interrogation signal to keys within the vehicle. Left-behind keys respond and send their unique ID(s) to the module's receiver. The processor obtains the unique ID(s) from the receiver and sets one or more inhibit flags in memory or equivalent to identify those keys as left-behind keys. The processor thereafter ignores commands from such left-behind keys, thereby rendering them temporarily inoperative until a valid unlock command is received form another source, whereupon the processor clears the inhibit flags from memory and restores the left-behind keys to active status.

Description

TECHNICAL FIELD

The present invention generally relates to electronic locking systems and keys therefore, and more particularly relates to means and methods for rendering electronic keys for such systems temporarily valid or invalid.

BACKGROUND

There are many applications today where electronic keys are used. A common example is with vehicles where an electronic key, sometimes in the form of a “fob” is enabled by the user to lock and unlock the vehicle doors, trunk, etc., raise and lower windows, start and stop the engine and/or perform a variety of other functions. Such systems are well known in the art.

The present invention is described for the case of electronic keys used to authorize vehicle door access, trunk access, and starting, but this is merely for convenience of explanation and not intended to be limiting. Persons of skill in the art will understand based on the description herein that the present invention applies to any electronic key function and not merely to a “lock” and “unlock” function and not merely to vehicles. Hence, such other electronic key functions are intended to be included in the words “lock” and “unlock” and such other locations, equipment, structures and/or apparatus are intended to be included in the word “vehicle.”

While prior art electronic keys and key systems are useful, they suffer from a number of limitations, well known in the art. Among these limitations is the presence of multiple keys. For example, when multiple keys exist and one or more is left behind in the vehicle (or structure), security can be compromised if an unauthorized person gains access to the “left-behind” key. Even if the vehicle is locked if there is an unauthorized entry and the intruder gains access to the left-behind key, he or she may be able to open doors, turn off a security alarm, start the vehicle or otherwise perform those functions able to be controlled by the left-behind key. Thus, a need continues to exist for improved systems and methods for dealing with multiple keys so that left-behind or other temporarily un-needed keys do not represent a security risk.

Accordingly, it is desirable to provide an improved electronic locking and key system and method that mitigate the risk presented by left-behind keys or other keys whose use may be compromised. It is desirable that the system be able to temporarily invalidate electronic keys that are left-behind or that otherwise present a security risk. In addition, it is desirable that the improved system and method be generally compatible with prior art electronic key systems. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.

BRIEF SUMMARY

An apparatus is provided for rendering electronic keys left behind in a vehicle temporarily inoperative. The apparatus comprises a vehicle security control module in wireless communication with the electronic keys and having a receiver adapted to receive commands from electronic keys, a processor, non-volatile memory and a short range transmitter, operatively coupled together. When the security module receives a valid LOCK command from any source it sends a short-range interrogation signal to any keys within the vehicle. Such left-behind keys respond and send their unique ID(s) to the module's receiver. The processor obtains the unique ID(s) from the receiver and sets one or more inhibit flags in memory to identify those as left-behind keys. The processor thereafter ignores commands or signals from such left-behind keys, thereby rendering them temporarily inactive. Such left-behind keys remain inactive until a valid UNLOCK command is received form another source, whereupon the processor clears the inhibit flags from memory and restores the left-behind keys to active status.

A method is provided for rendering electronic keys left behind in a vehicle temporarily inoperative. The method comprises receiving a LOCK command, sending a short range interrogation signal from the vehicle security control module to any keys left behind in the vehicle, receiving from any left-behind key(s) their unique ID(s), and setting one or more inhibit flags for the unique ID(s) of the left-behind keys, wherein the inhibit flags cause the vehicle to temporarily ignore further commands or signals received from such left-behind key(s). The left-behind keys remain invalidated until an UNLOCK command is received from other than an invalidated key and the one or more inhibit flags are cleared, thereby returning the left-behind keys to operating status.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and

FIG. 1 is a simplified electrical block diagram of the system of the present invention; and

FIG. 2 is a simplified flow chart of the method of the present invention.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.

FIG. 1 is a simplified electrical block diagram ofsystem20 of the present invention, comprisingsecurity control module41 in the vehicle (or structure) and one or more portableelectronic keys21 that may or may not be in the vehicle (or structure).Keys21 compriseprocessor22,non-volatile memory24,other memory25,transmitter26 andreceiver28, operatively coupled by bus or leads23. A state machine or other device may also be used as a replacement forprocessor22 and as used herein the word “processor” is intended to include such alternative.Antenna27 is provided fortransmitter26 andantenna29 is provided forreceiver28.Keys21 communicate with vehiclesecurity control module41 viasignals33,35 from and toantennas27,29 respectively.Transmitter26 ofkey21 andreceiver46 ofsecurity control module41 operate preferably at radio frequencies (RF). Thus,signal33 is preferably an RF signal. Receiver28 ofkey21 andtransmitter48 ofvehicle security module41 operate preferably at low frequencies (LF). Thus,signal35 is preferably a LF signal. However, the use of RF and LF signals is not essential. Other frequencies may also be used, provided thatsignal35 is limited in range, as will be explained in more detail later. Non-limiting examples of suitable frequencies are 300 to 500 MHz forsignal33 and 100 to 150 KHz forsignal35, but this is not intended to be limiting. Optical signals may also be used. For example, low power infrared may also be used forsignal35.

Vehicle mountedsecurity control module41 comprisesprocessor42,non-volatile memory44, other memory45,receiver46,transmitter48 and actuator(s)50, operatively coupled by leads orbus43.Antenna47 is provided forreceiver46, which receivessignals33 fromantenna27 andtransmitter26 ofkey21. Antenna(s)49 are provided fortransmitter48, which sendssignals35 toantenna29 ofreceiver28 ofkey21. Further LOCK/UNLOCK request sources51 are coupled tocontrol module41 by leads orbus52 and/or bywireless signal53. Non-limiting examples of further LOCK/UNLOCK request sources51 are central door lock switches, passive door lock switches, telematic services, key activated lock cylinders, alarm system activation/de-activation switches, and so forth.

In one manner of ordinary operation, activation of function buttons (not shown) onelectronic key21 by the user causesprocessor22 ofkey21 to retrieve the appropriate command code (e.g., LOCK, UNLOCK, etc.) and the key identification code (unique key ID) fromnon-volatile memory24. Persons of skill in the art will understand that a variety of operator selected functions may be included inkey21.Processor22 prepares a signal containing these codes in the appropriate format and passes it over bus or leads23 totransmitter26 where it is modulated onto an appropriate (e.g., RF) carrier bytransmitter26 and sent assignal33 viaantenna27 toantenna47 andreceiver46 ofcontrol module41. Receiver46demodulates signal33 and passes the recovered command and identification codes over bus or leads43 toprocessor42.Processor42 compares the received key ID code with valid key ID codes stored inmemory44 and, if approved, causes actuator(s)50 to execute the command received fromkey21. Thus, among other things,processor42 in cooperation withmemory44,45 andreceiver46, checks any signals received fromkey21 to insure that the ID of the transmitting key corresponds to a key authorized to issue commands to the particular vehicle.

Consider the situation where severalvalid keys21 exist, that is, more than one key is authorized to control vehicle functions viasecurity control module41. The user may take only one key with him/her when he or she exists the vehicle. One or more of the other keys are left behind in the vehicle. The portable key(s) are not the only mechanisms or circumstances able to lock or unlock the vehicle. In general, other lock/unlock request sources50 are often coupled to the vehicle. For example, and not intended to be limiting, the vehicle may be locked or unlocked by:

• a) Activation of a central locking request from the vehicle interior;
• b) Transmission of a “lock” command from nearby portable device such askey fob21;c)
• c) Transmission of a “lock” command from a remote service provider (e.g., one of several lock/unlock request sources50);
• d) Activation of a central locking request from a vehicle mounted exterior switch (e.g., another of several lock/unlock request sources50); and/or
• e) Passive locking upon detection of a reduction in electronic keys present in the vehicle's interior.
  It is desirable that the left-behind key or keys be rendered temporarily inactive so as to not constitute a potential security risk to the vehicle. This is accomplished by the present invention

When any lock activation, such as those listed above, is requested or occurs when the vehicle is in an OFF mode of operation, vehicle mountedsecurity control module41 determines whether anyelectronic keys21 have been left in the vehicle. Alternatively, the vehicle alarm system status (e.g., one of sources50) may be used as a surrogate for a lock and/or unlock commands, i.e., an ALARM ON command or status is equivalent to a LOCK command. Determining whether any keys remaining the vehicle is conveniently accomplished byprocessor42 causingtransmitter48 to sendinterrogation signal35 tokeys21 within range, that is, still within the vehicle. Havingtransmitter48 be a low frequency (LF) transmitter limits the range oftransmitter48 so thatonly keys21 that are still within the vehicle receiveinterrogation signal35. When a key receives such an interrogation signal, it responds acknowledging its continuing presence in the vehicle and giving its unique ID. Depending upon the vehicle configuration, it may be advantageous to useseveral antennas49 to provide interior vehicle coverage while still having negligible transmission field outside the vehicle. Whencontrol module41 receives a response or acknowledgement signal fromkey transmitter26 containing the unique ID of that key, it knows that such key has been left behind in the vehicle. For each key21 that has been left in the vehicle,processor42 causes an inhibit flag or other marker to be set inmemory44 to identify the left-behind key as temporarily invalid. Flag storage is performed innon-volatile memory44 to ensure proper security is maintained over time and voltage levels.

As long as this inhibit flag remains set, the vehicle will not respond to commands from that portable key. For each normal access or vehicle operation request where anyelectronic key21 is detected and has passed the normal ID and/or other authentication process, a further check is made of its flag to determine if it is temporarily invalid. If the inhibit flag or other marker is set indicating that the key is invalid, no vehicle action will result. If the inhibit flag or other marker is not set, the corresponding function will be appropriately performed. In the preferred embodiment, upon receipt of an authenticated unlock request from any electronic key21 that has been deemed to be also a valid key (ID match; no flag set, etc.) or from any other allowed unlock request source, the inhibit flags for all other electronic keys programmed to the vehicle will be cleared, thereby re-validating them all for subsequent use. The operation ofsystem20 will be more fully understood by reference to the method of the present invention illustrated inFIG. 2.

FIG. 2 is a simplified flow chart ofmethod100 of the present invention.Method100 begins withSTART102 and initial COMMAND RECEIVED FROM KEY?query104.START102 provides for initialization ofsystem20 in the key inhibit mode and desirably occurs when the ignition is switched off or the vehicle otherwise placed in the OFF state. Ininitial query104 it is determined whether or not the vehicle has received a command from one ofkeys21. If the outcome ofquery104 is FALSE (NO), abbreviated “N”, thenmethod100 advances to VALID LOCK COMMAND FROM VEHICLE? query106 wherein it is determined whether or not a valid lock command has been received from the vehicle, e.g., from one of other lock request sources51. If the outcome ofquery106 is FALSE (NO) then, as shown bypath107,method100 loops back toSTART102 andinitial step104. If the outcome ofquery104 is TRUE (YES), abbreviated as “Y”, thenmethod100 proceeds to KEY'S INHIBIT FLAG SET? query108 wherein it is determined whether the key issuing the command referred to instep104 has its inhibit flag set, to inactivate such key. If the outcome ofquery108 is TRUE (YES), then as shown bypath109,method100 loops back toSTART102 andinitial query104. This has the effect of ignoring commands received from a key whose inhibit flag is set while preparing to accept a valid command that originates other than from suchportable key21.

If the outcome ofquery108 is FALSE (NO) meaning that the command issuing key is not inhibited,method100 proceeds to RECEIVED COMMAND=LOCK? query110 wherein it is determined whether the received command is a LOCK command. If the outcome ofquery110 is TRUE (YES), thenmethod100 advances to SEND QUERY TOINSIDE KEYS step112, whereinsecurity control module41 sends localized interrogation orquery signal35 to one ormore keys21 that are within the vehicle. Those ofkeys21 that are within the vehicle respond at least with their unique IDs.Module41 then executes ANY KEYS LEFT BEHIND? query120 to determine which, if any, ofkeys21 have been left behind in the vehicle. Returning to query106, if the outcome ofquery106 is TRUE (YES) indicating thatsecurity module41 has received a valid LOCK command from a key21 or anotherlock request source51, thenmethod100 also advances to interrogatestep112 andquery120. Thus, if a LOCK command or request is received from eitherkeys21 or from anothersource51,method100 will determine whether any other ofkeys21 have been left behind in the vehicle, and through their unique IDs, which ofkeys21 have been left behind in the vehicle. If the outcome of ANY KEYS LEFT BEHIND? query120 is TRUE (YES),method100 advances to INHIBIT LEFT-BEHIND KEYS step122 wherein the keys identified insteps112,120 have their inhibit flags set so that they are no longer functional in whole or in part. Afterstep122,method100 advances to EXECUTECOMMAND step116. If the outcome of ANY KEYS LEFT BEHIND? query120 is FALSE (NO), thenmethod100 proceeds to EXECUTECOMMAND step116 wherein the received and authenticated command is executed.

Returning now to query110, if the outcome ofquery110 is FLASE (NO) indicating that the received command was not a LOCK command, thenmethod100 proceeds to RECEIVED COMMAND=UNLOCK? query114 wherein it is determined whether the received command is an UNLOCK command. If the outcome ofquery114 is FALSE (NO), thenmethod100 also proceeds to EXECUTECOMMAND step116. (This deals with the circumstance where the received command is neither a LOCK nor UNLOCK command.) If the outcome ofquery114 is TRUE (YES) indicating that the received command is an UNLOCK command, thenmethod100 proceeds to CLEAR INHIBIT(S)step118, wherein any inhibit flags previously set are cleared, thereby returning the corresponding key(s) to active status. Followingstep118,method100 proceeds to EXECUTECOMMAND step116 and thereafter loops back toSTART102 as shown bypath117.

In summary, a LOCK command causescontrol module41 to interrogate those ofkeys21 that may have been left behind in the vehicle and inhibits them from performing all or some of their normal functions until a valid UNLOCK command has been received from another source. The inhibit is conveniently accomplished by placing a flag or other marker in non-volatile memory incontrol module41, but any other means of accomplishing an equivalent inhibit result may also be used. A non-limiting example of an alternate arrangement is to send an inhibit command back to the inside-the-vehiclekeys using signal35 and storing the inhibit flag inmemory24 within the inhibited keys themselves. With this arrangement, each key would check its own inhibit flag before sending a command tomodule41 and if the flag is set, not transmit tomodule41 until its inhibit status is cleared. The same result is accomplished in that inhibited keys are inactivated untilmodule41 sends outsignal35 containing a CLEAR INHIBITS command to affectedkeys21.

While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. For example, inhibiting the left-behind keys by setting a flag in memory is but one of many ways in which the left behind keys may be rendered temporarily inactive. Accordingly, the words “setting a flag in memory” and “storing one or more inhibit flags” or equivalent are intended to include such alternative arrangements for temporarily invalidating the left-behind keys. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.

Claims (14)

1. A system for inhibiting electronic vehicle keys left behind in the vehicle when the vehicle doors are locked, comprising:

one or more portable keys adapted to send wireless command signals;

a vehicle security control module adapted to receive the wireless command signals from the one or more portable keys, wherein upon receiving a lock command signal, the vehicle security control module is configured to broadcast a short-range interrogation signal adapted to reach substantially only those of the one or more portable keys remaining within the vehicle, to receive a response containing a unique ID from those of the keys remaining within the vehicle thereby identifying themselves as left-behind keys, to store one or more inhibit flags identifying such left-behind keys as no longer valid and thereafter to ignore commands from such left-behind keys.

2. The system ofclaim 1 wherein the vehicle security control is further configured to retain the inhibit flags until an unlock command is received from a source other than a left-behind key.

3. The system ofclaim 1 wherein the security control module comprises:

a receiver configured to receive command signals from the one or more keys;

a non-volatile memory configured to store valid key ID(s) and the inhibit flags for left-behind keys;

a processor coupled to the receiver configured to interpret the command signals reaching the receiver, to test the unique ID received from any key to see whether there is a corresponding inhibit flag therefore stored in the non-volatile memory and if so, not processing a command received from such key; and

a transmitter configured to send the short range interrogation signal to the left-behind keys.

4. A method for inhibiting operation of electronic keys left behind in a vehicle, comprising:

receiving a lock command;

sending a short-range interrogation signal adapted to be received by any keys left behind in the vehicle;

receiving from any left-behind key(s) their unique ID(s); and

setting one or more inhibit flags for the unique ID(s) of the left-behind keys, wherein the inhibit flags cause the vehicle to ignore further commands received from such left-behind key(s).

5. The method ofclaim 4 further comprising:

receiving an unlock command from other than an inhibited key; and

clearing the one or more inhibit flags, thereby returning the left-behind keys to operating status.

6. The method ofclaim 4 further comprising, prior to the receiving a lock command:

determining first whether a command has been received from a key; and

if the first determining step yields NO, determining second whether a valid lock command has been received from the vehicle; and

if the second determining step yields NO returning to the first determining step; and

if the second determining step yields YES, proceeding to the sending step; and

if the first determining step yields YES, determining third whether the key's inhibit flag is set indicating that the key is invalid.

7. The method ofclaim 6 further comprising:

if the outcome of the third determining step yields YES, returning to the first determining step; and

if the outcome of the third determining step yields NO, determining fourth whether the received command is a lock command; and

if the outcome of the fourth determining step is YES, proceeding to the sending step; and

if the outcome of the fourth determining step is NO, determining fifth whether the received command is an unlock command; and

if the outcome of the fifth determining step is YES, clearing the one or more inhibit flags, thereby returning the left-behind keys to active status; and

if the outcome of the fifth determining step is NO, executing the received command.

8. The method ofclaim 5 further comprising after the clearing step, executing a received command.

9. Apparatus for inhibiting left-behind vehicle keys while not inhibiting other keys, comprising:

a security control module in the vehicle for receiving lock/unlock command signals from multiple sources, wherein the security control module comprises operatively coupled elements including:

one or more inputs for receiving lock/unlock commands;

a transmitter for sending interrogation signals to left-behind keys;

a receiver for receiving unique IDs from keys in response to the interrogation signals;

non-volatile memory for storing unique IDs of left-behind keys; and

wherein the apparatus further comprises one or more portable keys for sending command and ID signals to the security control module.

10. The apparatus ofclaim 9 wherein upon receiving a lock command, the security control module broadcasts through the transmitter the interrogation signal to the left-behind keys.

11. The apparatus ofclaim 10 wherein the left-behind keys respond to the interrogation signal by sending their unique ID(s) back to the receiver of the security control module, thereby identifying themselves as left-behind keys.

12. The apparatus ofclaim 11 wherein the security control module stores or marks the unique IDs in the non-volatile memory to identify such left-behind keys as being no longer valid and thereafter, until cleared, ignores commands from such left-behind keys.

13. The system ofclaim 12 wherein the left-behind keys remain invalid until the vehicle security control module receives an unlock command from a source other than a left-behind key.

14. An apparatus for inhibiting those vehicle electronic keys left behind in the vehicle when its doors are locked, comprising:

a vehicle security control module adapted to receive lock/unlock command signals from multiple sources;

one or more portable keys adapted to send command signals to the security control module and containing memory;

wherein upon receiving a lock command signal, the vehicle security control module broadcasts a short-range signal adapted to reach substantially only those of the keys remaining within the vehicle;

wherein in response to the short range signal, those keys remaining within the vehicle store an inhibit signal in their memory identifying themselves as no longer being valid keys, which thereafter until cleared, causes such keys to not send a valid command to the security control module.

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